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The overview describes the synergy between biological sciences and cellular structures processed by additive manufacturing to elucidate the significance of cellular structured implants in eliminating stress shielding and in meeting the bio-mechanical property requirements of elastic modulus, impact resistance, and fatigue strength in conjunction with the biological functionality. The convergence of additive manufacturing, computer-aided design, and structure-property relationships is envisaged to provide the solution to the current day challenges in the biomedical arena. The traditional methods of fabrication of biomedical devices including casting and mechanical forming have limitations because of the mismatch in micro/microstructure, mechanical, and physical properties with the host site. Additive manufacturing of cellular structured alloys via electron beam melting and laser powder bed fusion has benefits of fabricating patient-specific design that is obtained from the computed tomography scan of the defect site. The discussion in the overview consists of two aspects - the first one describes the underlying reason that motivated 3D printing of implants from the perspective of minimising stress shielding together with the mechanical property requirements, where the mechanical properties of cellular structured implants depend on the cellular architecture and percentage cellular porosity. The second aspect focuses on the biological response of cellular structured devices. [ABSTRACT FROM AUTHOR]

Ti-6Al-4 V and Ti-6Al-4 V ELI alloys were surface modified with nanotube layers by electrochemical anodisation technique. Osteoblast cell viability and their osteogenic behaviour were studied. It was found that the pore diameters of the nanotubes were in the range of 70–105 nm for Ti-6Al-4 V sample and 60–130 nm for Ti-6Al-4 V ELI sample. Porosity was calculated to be in the range of 75–85% of the total volume of formed nanotubes. Pores were arranged in a self-organised nanotube structure and the nanotubes emanated from the pores. MG63 cells cultured on the samples for 1, 7 and 14 days showed significant osteoblast cell growth on Ti-6Al-4 V ELI surface as compared to the grade 5 titanium alloy. CCK-8 assay results confirmed better cytocompatibility of the Ti-6Al-4 V ELI nanotube surface than the Ti-6Al-4 V surface which were ascribed to various inert or toxic ions released to the medium from Ti-6Al-4 V matrix. [ABSTRACT FROM AUTHOR]

The objective is to study fatigue failure of gears and bearings during processing of rebars and evaluate their performance under cyclic stresses. Mechanical vibration was measured on gears and bearings to determine efficiency and to avoid fatigue failure of components. These components are used during hot rolling to plastically deform steel billets and are exposed to cyclic and variable load stresses. The total amount of energy loss in the form of mechanical vibration was determined, and it was concluded that the materials selected for gears and bearings complied with the design criteria by failing progressively and not suddenly. Consequently, it was also concluded that the energy efficiency on reheating is strongly affected by fatigue failure of any of the components during hot rolling. [ABSTRACT FROM AUTHOR]

Pure magnesium implants have a problem of faster degradation which leads to the collapse of the implant before the recovery of physiological organ. A new magnesium alloy viz Mg-2Zn-0.5Nd (ZN20) is designed using a well-known alloying method to decrease the degradation rate of pure magnesium metal and its implants so as to match the tissue recovery rate. MTT assay of the ZN20 alloy via a direct contact method for 2, 4 and 6 days using MC3T3-E1 cells showed cytotoxicity. Whereas, the MTT assay results of this alloy via ion-extract method showed non-cytotoxic behaviour. The degradation rate of ZN20 alloy in SBF was ~2.5% in 16 days which is comparable to the rate of regeneration and recovery of physiological tissue. The pH of the outer solution after degradation of ZN20 alloy for 3 days was around 9.31 ± 0.05 which was higher than the initial pH of SBF used (pH 7.4). The reason for the cytotoxic behaviour of this alloy could be the increase in pH of immersion solution with the degradation of the alloy. Interestingly, the scanning electron microscope images followed by EDX spectrum of ZN20 alloy showed deposition of white crystalline mineralisation product (apatite) after 3, 7, 11 and 16 days of incubation in SBF at 37°C. The FT-IR spectrum and X-ray chromatogram of the white substance confirmed the deposition of apatite (calcium phosphate) on their surfaces. These results concluded the bioactivity of ZN20 alloy and thus could be used as an implant material for regeneration of bones/tissues. [ABSTRACT FROM AUTHOR]

Nanomaterials are attractive in biological analysis due to their advantages such as high surface-to-volume ratio, surface plasmonic effect, ease to be chemically modified, and have been applied for diagnosis and therapy of diseases like cancer, cardiovascular and infectious diseases. Meanwhile, microfluidic devices provide an ideal platform for disease diagnosis with a small sample, and for therapy evaluation by recapitulating in vivo like 3D models. The application of nanomaterials in microfluidic devices as capturing, signaling and energy transferring components has combined the advantages of both technologies. Here we focused on recent advances of nanomaterials incorporated microfluidic devices for analysis of proteins, nucleic acids, cells, and small molecules with various analytical methods such as optical, electrochemical, chemiluminescent approaches. Moreover, microfluidic based biological systems were used to evaluate nanoparticles based therapies including photodynamic therapy, photothermal therapy and controlled drug delivery. The combination of nanotechnology and microfluidic technology hold great potential toward medical and clinical applications in the future. [ABSTRACT FROM AUTHOR]

Magnesium alloys have significant potential as load-bearing biodegradable implants. However, controlling the biodegradation rate in the physiological environment is a challenge. In this study, we explore three magnesium alloys containing rare earth elements in terms of biodegradable behavior in simulated body fluid. The chemistry and processing of these alloys (Mg-2Zn-2Gd, Mg-3Sn-1Mn-0·6La, Mg-3Gd-1·7Y-0·5Zr) was designed to exhibit different strength based on grain size-strength relationship in addition to precipitation strengthening. Surface studies indicated the formation of rapid and stable growth of apatite layer on ultrafine grained Mg-2Zn-2Gd alloy as compared to relatively coarse-grained Mg-3Sn-1Mn-0·6La and Mg-3Gd-1·7Y-0·5Zr alloys. While, the pH change was initially higher for all the three alloys, but changed with time. Mg-2Zn-2Gd exhibited least degradation rate as compared to other two alloys. The differences in the biodegradation behavior of the alloys is attributed to the degree of stability of apatite layer on the surface, which was governed by grain size, rare-earth containing precipitates along the grain boundaries (including matrix) and surface energy. [ABSTRACT FROM AUTHOR]

The functional response of polymeric materials including biocompatibility and biodegradability in context of biomedical devices is governed by the macromolecular architecture, notably, random, block, star, graft and cross-linked polymers. The change in macromolecular architecture from diblock to triblock, linear to cyclic, star to dendritic, network to cross-linked (supra-molecular to covalent), etc. and their synthetic conditions govern the formation and properties of different materials for biological applications. For example, different self-assemblies and gelations from block copolymers, multi-molecular and uni-molecular self-assemblies from star polymers and dendrimers, unique thermal and hydrodynamic properties of cyclic polymer based systems compared to other polymeric materials, etc. A part of the review describes the different synthetic methods that are currently being employed to obtain biomaterials. While, the other part underscores the significance of macromolecular architectures on the properties of obtained materials. In summary, we elucidate here structure-molecular parameter-property relationships of macromolecular architecture in context of biomedical devices. [ABSTRACT FROM AUTHOR]

The objective of the study described here is to fundamentally elucidate the biological response of 3D printed Ti-6Al-4V alloy mesh structures that were surface modified to introduce titania nanotubes with an average pore size of ∼80 nm via an electrochemical anodization process from the perspective of enhancing bioactivity. The bioactivity of the mesh structures were analyzed through immersion test in simulated body fluid, which confirmed the nucleation and growth of fine globular nanoscale apatite on the nanoporous titania-modified (anodized) mesh structure surface, and agglomerated apatite with fine flakes of apatite crystals on as-fabricated mesh structure surface, that were rich in calcium and phosphorous. The cellular activity of bioactive anodized mesh structure was explored in terms of cell–material interactions involving adhesion, proliferation, synthesis of extracellular and intracellular proteins, differentiation, and mineralization. Cells adhered with a sheet-like morphology on as-fabricated mesh structure, whereas, on anodized mesh structure, numerous filopodia-like cellular extensions interacting with nanotube pores were observed. The formation of a bioactive nanoscale apatite, cell–nanotube interactions as imaged via electron microscopy, higher expression of proteins (actin, vinculin, fibronectin, and alkaline phosphatase (ALP)), and calcium content points toward the determining role of anodized mesh structure in modulating osteoblasts functions. The unique combination of nanoporous bioactive titania and interconnected porous architecture of anodized titanium alloy mesh structure provided a multimodal roughness surface ranging from nano to micro to macroscale, which helps in attaining strong primary and secondary fixation of the implant device along with the pathway for supply of nutrients and oxygen to cells and tissue. [ABSTRACT FROM AUTHOR]

The successful integration of a biomedical device is governed by the surface properties of the material and also depends on the interaction with the physiological fluid. In this regard, bulk nanostructured materials are recently being recognised as potential implant materials alternative to conventional materials. The potential application of such next generation materials as biomedical implants has recently been evaluated by investigating the effect of wide range of grain sizes on multiple cell activities. In this review, recent advances in biomedical applications of bulk nanostructured materials are highlighted with special focus on the effect of phase reversion-induced nanograined size on protein adsorption and cell–material interactions. Furthermore, the effect of grain structure on antimicrobial effect is also discussed. Osteoblasts functions and cellular activity are promoted on the nanostructured surface in relation to the coarse-grained counterpart. Finally, the advantages of phase reversion approach to produce multifunctional bio-implant materials are addressed. [ABSTRACT FROM PUBLISHER]

The concept of phase reversion involving severe cold deformation of metastable austenite to generate strain-induced martensite, followed by a specific temperature-time annealing sequence, was used to obtain grain size varying typically from nanograined/ultrafine-grained (NG/UFG) to coarse-grained (CG) regime with the objective to elucidate the interplay between strain hardening behavior and grain structure. The study underscores that irrespective of the grain structure and mechanisms operating during deformation (twinning vs. strain-induced martensite), the generic nature of strain hardening is unaltered. However, there were subtle differences in the three-stage strain hardening ability that were governed by noticeably different deformation mechanisms. There was transition in deformation mechanism from essentially nanoscale twinning in NG/UFG and sub-micron grained (SMG) structures to strain-induced martensite transformation in the fine-grained (FG) and CG structures, a behavior related to increase in the stability of austenite with decrease in grain size. [ABSTRACT FROM AUTHOR]

Glucose serves as the primary source of energy to cells in our physiological system, enabling them to perform important functions including: nerve cell conduction, muscle cell contraction, active transport and production of chemical substances. Lower blood glucose concentration can cause seizure, loss of consciousness and irreversible cell damage. While excessive blood glucose concentration has a detrimental effect (glucotoxicity) potentially causing blindness, renal failure, cardiac and peripheral vascular disease, and neuropathy. Thus, simultaneous detection of intracellular and extracellular glucose is critically important from the view point of diagnosis and to understand the relationship between intracellular glucose and the metabolic control systems within the cells. The focus of development of third generation of biosensors is driven by nanotechnology. In this regard, carbon dots are promising building blocks for biosensors because of their unique optical properties and biocompatibility. They can be chemically modified to facilitate detection of biologically relevant molecules with high sensitivity and selectivity. We describe here our preliminary studies dealing with the synthesis, characterisation and intracellular response of glucose to carbon dots and discuss their potential as effective biosensors. Also discussed are the basic principles underlying the detection of glucose and the progress made in the development of biosensors for glucose detection. [ABSTRACT FROM AUTHOR]

There is currently a strong interest in nano- and ultrafine grained planar surface and coatings in the biomedical community, but there is a lack of understanding with regard to the interplay between grain size and cell differentiation. Motivated by our previous studies on the interplay between grain structure and biological response, we describe here the influence of grain size from nano- to coarse grain on osteoblast differentiation and mineralisation. This aspect constitutes the objective of the study. Experiments on the interplay between grain structure and osteoblast functions indicated that cell differentiation and mineralisation varied with grain size and were favourably modulated on the nanograin (NG) and ultrafine grain (UFG) surface, consistent with alkaline phosphatase activity. Furthermore, it is elucidated that the grain structure strongly influences the ability of the surface to form a well mineralised bone-like extracellular matrix by secreting bone markers, which in turn is governed by grain structure-hydrophilicity relationship. The study demonstrates potential for a new branch of nanostructured materials for biomedical applications. [ABSTRACT FROM AUTHOR]

Protein adsorption is the first of a complex series of events that regulate cell adhesion and cellular activity and define the hallmark of biological reactions at the biointerface. In this regard, materials with submicrometre to nanometre sized grains by virtue of their high grain boundary length to grain size ratio are excellent vehicles to fundamentally understand self-assembly of preadsorbed proteins and consequent cellular activity. The model protein (albumin) on a nanograined surface had the resemblance of 'leaf-like' in contrast to 'bare branch of a tree' on the coarse grained counterpart with consequent impact on biological functions, for instance, osteoblast response. This raises a fundamental question on the interplay between grain size and surface induced arrangement of plasma proteins into organised structures. It is envisaged that in a given polycrystalline material, the self-assembly of proteins at a biointerface is governed by grain structure because of differences in surface energy and microrheological behaviour that controls the kinetics and thermodynamics of protein adsorption. Furthermore, our capability to synthesise and process biomaterial surfaces with tailored surface morphology and consequently control assembly of proteins provides the possibility of eliciting specific, timely and desirable response from the surrounding cells and tissues necessary for implant efficiency. Studies on the early stages of protein adsorption are expected to impact interfacial processes including neurobiology, where the assembly of soluble proteins as organised structure is potentially considered to be characteristic of neurodegenerative diseases such as Parkinson's and Alzheimer's disease. This is particularly important when the most important relaxation mechanisms such as desorption and conformational changes alter adsorption and are impacted by grain structure and associated surface energy. [ABSTRACT FROM AUTHOR]

Photoluminescent semiconductor quantum dots (QDs) are of significant interest for bioimaging and fluorescence labelling. In this regard, the design and synthesis using a chemical hydrolysis approach is described of high sensitivity and high specificity non-toxic ZnO QDs (∼5 nm). The ZnO QDs, with long term stability of up to 12 months, exhibited strong green yellow emission on doping with small concentration of manganese, which is tunable to the near infrared biological window (about 650-770 nm). Furthermore, the embedding of ZnO QDs on silica nanospheres led to a significant increase in photoluminescence intensity rendering them suitable for bright QD based probes. [ABSTRACT FROM AUTHOR]

Economically viable ZnS and Cd doped ZnS nanorods were synthesised in egg albumin matrix for drug carrier and bioimaging to develop a new generation of effective drug carrier and imaging for cancer therapy. This system is capable of overcoming biophysical, biological and biomedical barriers that the physiological system encounters against conventional cancer therapies. The sulphide nanorods were formed from the hydrolysis of thiourea, where the albumin acts as a structural agent that guides in the formation of nanorods. [ABSTRACT FROM AUTHOR]

There is currently a trend toward increased usage of polymeric materials as functional materials because they are likely to experience force in the nanometer range. Thus, we describe here nanoindentation experiments in a polymer nanocomposite system with dif-ferent nanoclay content and compare with the pristine counterpart. A Berkovich nano-indenter was used to conduct nanoscale deformation experiments using a load of 1-5 mN. The nanoindentation contact properties of relevance to functional applications notably hardness, modulus, and adhesion forces were studied. The addition of8wt% of nanoclay to high density polyethylene led to an increase in the indentation hardness by ~30% and modulus by 25%. Furthermore, using load-displacement plots, the adhesion force between the indenter tip and the material's surface was measured. The adhesion force that is related to the stickiness of the surface was observed to decrease on the introduc-tion of nanoclay in the polymer because of an increase in hardness and modulus of the nanocomposite, leading to a decrease in the area of interaction between the indenter tip and the probed surface. The resistance to nanoindentation of the nanocomposite is explained in terms of a shift in von Mises stress from the surface to the subsurface in the nanocomposite. [ABSTRACT FROM AUTHOR]

The primary challenge in the delivery of a drug to a tumour site is to target the anticancer drug specifically into and around tumours at concentrations that will decrease their growth and/or viability. Excellent vehicles to achieve targeted drug delivery are magnetic nanocarriers. A approach to accomplish this objective is to fabricate a novel temperature and pH-responsive magnetic nanocarrier that combines tumour targeting and controlled release. In addition to controlled release, these carriers simultaneously offer the possibility of imaging the delivery process by magnetic resonance imaging. The novel aspect of this approach is the combination of thermal and pH sensitivity of the drug containing shell with magnetic properties of the core in a single unit. Furthermore, application of an external magnetic field will heat the nanoparticles and thus nanoparticle containing cells. The targeted heat will aid in the killing of tumour cells. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites, or more appropriately polymer nanostructured materials, represent a radical alternative to the conventional filled polymers and polymer blends, in which discrete constituents on the order of a few nanometres are incorporated in the polymer matrix. In the last decade, the utility of inorganic nanoparticles as additives to enhance polymer performance has been established and now provides numerous commercial opportunities, ranging from advanced aerospace systems to commodity plastics. The incorporation of low volume additions (1–5 wt-%) of highly anisotropic nanoparticles, such as layered silicates or carbon nanotubes, have resulted in property enhancements with respect to the neat polymer that are comparable with that achieved by conventional loadings (15–40 wt-%) of traditional fillers. The lower loadings facilitate processing and reduce component weight. In addition, unique value added properties not normally possible with traditional fillers were also observed, such as high stiffness, reduced permeability, optical clarity and electrical conductivity have been achieved. However, the development of chemical and processing procedures to disrupt the low-dimensional crystallites (tactoids and ropes) to achieve uniform distribution of the nanoelement (layered silicate and single wall carbon nanotube respectively) continues to be a challenge. Even less developed are approaches to provide spatial and orientational control of the hierarchical morphology. There exists an immense potential for polymer nanocomposites, in particular, polypropyelene–clay nanocomposites paving the way for future technologies for the materials community at large. [ABSTRACT FROM AUTHOR]

The magnetic behaviour of nanocrystalline ferrite is compared with the diluted dispersion systems containing 10–40 wt-% nickel ferrite in a polyethylene matrix. The zero field cooled (ZFC)/field cooled (FC) magnetic measurements [M(T)] and M(H) measurements suggest strong evidence of interparticle interaction (dipolar surface interactions) which cannot be ignored even in 10 wt-% nickel ferrite–polyethylene diluted system. The general magnetic behaviour of diluted dispersion is similar to that of the undiluted nickel ferrite. However, coercivity, remanence and saturation magnetisation are altered. The changes in the magnetic data are discussed in terms of magnetisation interactions that encourage flux closure configuration. [ABSTRACT FROM AUTHOR]

The dynamic embrittlement of low alloy steels with two different flow stresses at a low partial pressure of oxygen is presented. The low alloy steel with a higher flow stress experienced a relatively higher degree of dynamic embrittlement compared with the steel with a lower flow stress. Pronounced surface relief originated on the surface of intergranular facets, and is defined in terms of a surface deformation parameter determined from atomic force microscopy. [ABSTRACT FROM AUTHOR]

Copper-chromium alloys exhibit a severe intermediate temperature loss in ductility during uniaxial tensile loading that has the characteristics of dynamic embrittlement. The dynamic embrittlement is characterised by intergranular fracture caused by stress induced ingress of sulphur to the grain boundaries followed by decohesion. [ABSTRACT FROM AUTHOR]

Nanocrystalline nickel and zinc ferrites synthesised using a microemulsion technique were characterised by high resolution transmission electron microscopy and vibrating sample magnetometry. A narrow and uniform distribution of crystals of size range 5--8 nm, distinguished by a clear lack of saturation magnetisation at 9 kOe, were obtained. Also, no coercivity or remanence was observed. [ABSTRACT FROM AUTHOR]

To use the unique properties of nanocrystalline ferrites in magneto-optical devices, it is important that they have a narrow particle size distribution. The present paper illustrates the potential of the microemulsion technique to synthesise different nanocrystalline ferrites (nickel ferrites, zinc ferrites) with such a narrow particle size distribution. The results of preliminary characterisation by field emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction are presented, confirming the nanocrystalline and spinel crystallographic structure of nickel ferrites. [ABSTRACT FROM AUTHOR]

Anodisation with electrochemical cathodic deposition method was employed to modify the surface of Ti implants with a bilayer coating made of Sr- doped titania (Sr-TiO2) and hydroxyapatite doped with magnesium (Mg-HAp). The Mg-HAp/Sr-TiO2 bilayer coating was compared with pure TiO2 and Sr-TiO2 single-layer coating. The Sr incorporation into TiO2 and Mg substitution into HAp strengthened their bioactive properties. The tensile test indicated increase in the mechanical strength of the bilayer coated substrate compared to pure TiO2 substrate. Moreover, the study indicated that the Sr and Mg ions were uniformly incorporated into the Mg-HAp/Sr-TiO2 bilayer coating with significantly higher roughness and hydrophilicity compared to the control. In vitro studies with osteoblasts cells had a superior response to the Mg-HAp/Sr-TiO2 bilayer surface. It was found that a bilayer Mg-HAp/Sr-TiO2 coating on Ti implants promotes bioactivity and has superior adhesion strength necessary for osseointegration and bone healing. [ABSTRACT FROM AUTHOR]

The main purpose of this work is to study how the morphology of nanofillers and dispersion and distribution level of inorganic nanofiller influence the impact behavior and fracture probability of inorganic filler filled industrial high-density polyethylene nanocomposites. For this study, nanoclay and nano-CaCO3 fillers–high-density polyethylene mixings (0, 1, 3, 5 wt.% high-density polyethylene) was prepared by melt-mixing method using a compounder system. The impact behavior was examined by charpy impact test, scanning electron microscopy, and probability theory and statistics. The level of the dispersion was characterized with scanning electron microscopy energy dispersive X-ray spectroscopy analysis. The results showed rather good dispersion of both of inorganic nanofiller, with a mixture of exfoliated and confined morphology. The results indicated that the impact strength of the industrial nanocomposite decreased with the increase of inorganic particulate content. The impact reliability of the industrial nanocomposites depends on the type of nanofillers and their dispersion and distribution in the matrix. [ABSTRACT FROM AUTHOR]

A covalently cross-linked injectable hybrid hydrogel, namely, alginate/poly(amidoamine) (PAMAM), with the objective of cell delivery was innovatively designed and synthesized using tetra-amino-functional PAMAM dendrimer as the cross-linker. With the increase in percentage of PAMAM cross-linker, the pore size and swelling ratio of hydrogels were in the range of 57 ± 18 μm to 88 ± 25 μm and 110 ± 16 to 157 ± 20, respectively. The study of attachment and proliferation of MC3T3-E1 pre-osteoblasts using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay through indirect and direct contact methods indicated a continuous increase in metabolically active live cells with time, implying non-cytotoxicity of the synthesized hydrogel. The live–dead assay showed >95% of live cells for alginate/PAMAM hydrogels, suggesting viability of the encapsulated cells. When the percentage of PAMAM cross-linker in alginate/PAMAM hydrogel was increased from 5 to 25, the percentage degradation rate decreased from 1.1 to 0.29%/day. Given that the poly(ethylene glycol) is commonly used cross-linker for hydrogel syntheses, we compared the behavior with poly(ethylene glycol). The incorporation of poly(ethylene glycol) in alginate/PAMAM hydrogel reduced the activity of MC3T3-E1 cells and their viability compared to the alginate/PAMAM hydrogels. The protonation of amino groups in alginate/PAMAM injectables under physiological conditions led to the formation of cationic hydrogels. These cationic hydrogels showed enhanced cell encapsulation and attachment ability because of electrostatic interaction with negatively charged cell surface as determined by cell adhesion and extensions from scanning electron microscope and vinculin assay and ability of in situ calcium phosphate mineralization. These observations point toward the potential use as an injectable scaffold for cell delivery and tissue engineering applications. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the dependence of the giant magnetoresistance effect, the coercivity, the coupling field, and the resistivity on film deposition at low-substrate in spin valve multilayers of the general type metallic glass. Methodology of the study; Results and discussion; Conclusions.

Presents a study that determined the giant magnetoresistance (GMR) values exceeding 21% in symmetric spin valves. Reason for the interest in symmetric spin valves; Details of the magnetoresistance measurements performed; Temperature dependence of the GMR of a typical sample; Dependence of the GMR in the symmetric spin valve structures on the thickness of the cobalt layers.

Glucose serves as the primary source of energy to cells in our physiological system, enabling them to perform important functions including: nerve cell conduction, muscle cell contraction, active transport and production of chemical substances. Lower blood glucose concentration can cause seizure, loss of consciousness and irreversible cell damage. While excessive blood glucose concentration has a detrimental effect (glucotoxicity) potentially causing blindness, renal failure, cardiac and peripheral vascular disease, and neuropathy. Thus, simultaneous detection of intracellular and extracellular glucose is critically important from the view point of diagnosis and to understand the relationship between intracellular glucose and the metabolic control systems within the cells. The focus of development of third generation of biosensors is driven by nanotechnology. In this regard, carbon dots are promising building blocks for biosensors because of their unique optical properties and biocompatibility. They can be chemically modified to facilitate detection of biologically relevant molecules with high sensitivity and selectivity. We describe here our preliminary studies dealing with the synthesis, characterisation and intracellular response of glucose to carbon dots and discuss their potential as effective biosensors. Also discussed are the basic principles underlying the detection of glucose and the progress made in the development of biosensors for glucose detection. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including glucose biosensors, the use of functionalized gold nanoparticles to detect stimulants, and cellulose-zinc oxide (ZnO) hybrid film-based biosensors.

An introduction to the journal is presented in which the editor discusses challenges in the design and development of biosensors.

The effect of dew point on the selective oxidation behavior, microstructure and mechanical properties of a high-Al low-Si dual phase steel is elucidated. The results showed that as dew point is increased from-30°C to +5°C, internal oxidation of alloying elements occurs, and consequently the mass of external oxides decreases, which improves the galvanisability of steel sheets. It was also observed that the dew point had an impact on the microstructure and mechanical properties of the experimental steel. With the increase of dew point, the decarburization layer on the surface was increased, leading to inferior mechanical properties. Compared with the industrial steel, the high-Al-low-Si DP steel exhibited excellent galvanisability under identical annealing conditions. [ABSTRACT FROM AUTHOR]

In recent years, magnesium alloys have attracted significant attention as a new class of biodegradable implant materials, because of their superior biocompatibility and low modulus. We describe here the inhibition of bacterial colonisation and biofilm formation on surfaces of Mg-2Zn-2Gd alloy with different grain structures (~44 µm to ~710 nm) obtained via multiaxial forging. Surface energy and contact angle measurements using goniometer and wettability were assessed with water, SBF, n-Hexane and DMEM. The higher surface energy of ultrafine-grained Mg-2Zn-2Gd alloy led to the release of more Mg+2 ions at an early stage, which consequently increased the pH of fluid in the vicinity of the implant, therefore producing unfavourable environment for the survival ofEscherichia coli(E. coli) bacteria. This led to damage of bacterial cell walls thereby reducing their adhesion. In summary, the study underscores that grain size had a significant impact on antimicrobial behaviour. [ABSTRACT FROM AUTHOR]

Metallic implant materials used in load-bearing applications are inert in nature in their native state. The surface properties of the material and its interaction with the surrounding physiological fluid determine the success of the biomedical implant. In this regard, bioactive nanostructured coatings are being recognised as potential approach to enhance the biological and corrosion properties of the conventional inert materials. In this review, recent advances in biomedical applications of nanostructured hydroxyapatite coatings on stainless steel implant materials are highlighted with special focus on the electrochemical deposition of hydroxyapatite and their consequent biological activity. Furthermore, osteoblasts functions and cellular activity on the nanostructured hydroxyapatite coatings processed by other techniques is also discussed. The potential application of such next generation materials as biomedical implants is also addressed. [ABSTRACT FROM PUBLISHER]

The objective of this study is to examine the mechanical, thermal, and physical properties of industrially produced nano-CaCO3 filled high-density polyethylene nanocomposites. For this purpose, 1.0, 3.0, 5.0, 10.0, and 15.0 wt.% loading of nano-CaCO3 filled high-density polyethylene nanocomposites were prepared by the melt mixing method using a compounder system, which consist of industrial banbury mixer, single screw extruder, and granule cutting. The effect of nano-CaCO3 on mechanical, thermal, and physical properties of nano-CaCO3/HDPE nanocomposites was investigated. As a result of all experiments, the tensile strength of nano-CaCO3 filled high-density polyethylene nanocomposite increased about 5% with addition of 1.0 wt.% nano-CaCO3. But did not increase further as more nano-CaCO3 was added. The flexural strength of nano-CaCO3 filled high-density polyethylene nanocomposite increased about 4.5% with addition of 15.0 wt.% nano-CaCO3.Then increased slightly as the nano-CaCO3 content increased to 15.0 wt.%. The tensile and flexural modulus of high-density polyethylene were significantly improved after (from 1.0 wt.% up to 15.0 wt.%) addition of nano-CaCO3. The tensile elongation at break and shore D hardness was consistently decreased with the addition of nano-CaCO3. The nano-CaCO3 filled high-density polyethylene nanocomposites were determined to have lower impact energy level than neat high-density polyethylene. The occurred fracture areas with the impact were detected by scanning electron microscopy examination. It is understood that fracture surface morphology changes when nano-CaCO3 ratio increases. The fracture surface changes were examined to determine the fracture mechanism of nano-CaCO3 filled high-density polyethylene nanocomposites. Density, melting flow index, differential scanning colorimetry, and vicat softening temperature were used to characterize the physical and thermal properties of the nanocomposites. The X-ray diffraction, the fourier transform infrared spectrophotometry, the transmission electron microscopy, and the scanning electron microscopy were used to analyze the structural characteristics of the nanocomposites. It is concluded that the addition of the nano-CaCO3 in high-density polyethylene has significantly influenced the mechanical, thermal, and physical properties of the nanocomposites. [ABSTRACT FROM AUTHOR]

The endogenous electric field plays a determining role in impacting biological functions including communication with the physiological system, brain, and bone regeneration by influencing cellular functions. From this perspective, the objective of the study described here is to elucidate the effect of external electric field under dynamic conditions, in providing a guiding cue to osteoblasts in terms of cell–cell interactions and synthesis of prominent adhesion and cytoskeleton proteins. This was accomplished using pulsed direct current electric field of strength 0.1–1 V/cm. The electric field provided guided cue to the cells to migrate toward cathode. Membrane blebbing or necrosis was nearly absent in the vicinity of cathode at 0.1 and 0.5 V/cm electric field strength. Moreover, a higher cell proliferation as well as higher expression of vinculin and densely packed actin stress fibers was observed. At anode, the cells though healthy but expression of actin and vinculin was less. We underscore for the first time that the biological functionality can be favorably modulated on 3D printed scaffolds in the presence of electric field and under dynamic conditions with consequent positive effect on cell proliferation, growth, and expression level of prominent proteins. [ABSTRACT FROM AUTHOR]

Magnesium alloys have recently attracted significant attention as a new class of biodegradable implant materials. The primary focus has been on mechanical properties, biological response and biodegradation. The alloys of current interest concern magnesium alloys with rare earth (RE) elements. We describe here the state-of-the-art knowledge on the corrosion behaviour of Mg-RE alloys in conjunction with the biological behaviour and mechanical properties. The addition of RE elements in magnesium alloys provide benefits of improved corrosion resistance via reduction in galvanic sites together with superior mechanical properties. [ABSTRACT FROM PUBLISHER]

The main aim of this paper is to introduce mechanical, thermal and surface properties of produced industrially HDPE-based nanocomposites. For this purpose, 1.0, 2.0, 3.0, 4.0 and 5.0 wt.% loading of nanoclay-reinforced HDPE nanocomposites made from the HDPE matrix were prepared by the melt mixing method using a compounder system, which consist of industrial banbury mixer, single screw extruder and granule cutting. The effect of nanoclay on mechanical, thermal and surface properties of nanoclay/HDPE nanocomposites was investigated. The tensile and flexural strength of nanoclay/HDPE nanocomposite increased by about 5% and 7%, respectively, with addition of 1.0 wt.% nanoclay. But then it decreased slightly as the nanoclay content increased to 5.0 wt.%. The tensile modulus and tensile elongation were decreased with the addition of 1.0 wt.% nanoclay, but did not increase further as more nanoclay was added. The flexural modulus of HDPE was significantly improved after (from 1.0 wt.% up to 5.0 wt.%) addition of nanoclay. It was found that the scratch resistance of nanoclay/HDPE nanocomposite improved with addition of the nanoclay by SEM examination. Density, melting flow index (MFI), differential scanning colorimetry (DSC), and vicat softening temperature (VICAT) were used to characterize the physical and thermal properties of the nanocomposites. The X-ray diffraction (XRD), the Fourier transform infrared spectrophotometry (FTIR), and the scanning electron microscopy (SEM) were used to analyze the structural characteristics of the nanocomposites. It is concluded that the addition of the nanoclay in HDPE has significantly influenced the mechanical, thermal, and surface properties of the nanocomposites. [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs), consisting of five or more elements with nearly equal atomic composition with one another (5–35%), are new-generation alloys that have attracted signifi)cant interest since their advent in 2004 because of their unique structural and mechanical properties and thermodynamic and chemical stability. Some characteristics, including high mechanical strength at elevated temperatures, high ductility and fracture toughness at cryo)genic temperatures and high corrosion, erosion and wear resistance, have been demonstrated for HEAs that outperform traditional alloys and superalloys. Laser-cladding (LC) is an additive manufacturing technique that has good feasibility in designing and processing HEAs for advanced structural components and protective coatings. This overview provides a glimpse of recent advances in LC of HEAs in terms of design fundamentals, metallurgical phase and microstructure, specific properties for advanced coating applications and the effect of ceramic particles reinforcement in LC deposition of HEA coatings. [ABSTRACT FROM AUTHOR]

A Ti3C2 MXene/Ti composite powder was developed through surface modification and powder coating for producing a high-performance titanium matrix composites (TMCs) by laser power bed fusion. Introducing MXene rarely changed the original sphericity and flowability of Ti powder while it slightly enhanced the laser absorption capacity of Ti powder. The printing conditions in turn affected the morphology and distribution of MXene in as-printed composites. At optimised printing parameters, majority of MXene with high structural integrity and uniform distribution remained along the grain boundaries of as-printed composites, and a combination of high surface quality, geometrical accuracy and densification was obtained. The remaining MXene played the synergy of pulling-out effect and load transfer role, which increased the yield strength from 530 to 710 MPa, while retaining good ductility (elongation of 19.8%). Compared with ASTM standard cast Ti64 alloy, our MXene/Ti composites also exhibited superior comprehensive tensile properties and excellent strength-ductility synergy. [ABSTRACT FROM AUTHOR]

Polycrystalline nanoparticles of Al-doped and Ce-co-doped ZnO were processed through sol)gel co-precipitation. Crystallite sizes determined from XRD were in the range of 10.90 to 48.77 nm. FTIR spectra indicated a stretching mode of Zn-O bond. The insertion of Al and Ce at Zn-O site created Al-O and Ce-O bonds. UV-vis spectra favoured the formation of impurity levels by doping and co-doping. Their overlapping with the conduction band edge led to the reduction of band-gap. Blue-green emission which arises from radiative recombination of a photogenerated hole with an electron occupying oxygen vacancy was observed in photo)luminescence spectra. FESEM suggested granular growth in undoped ZnO which changed to diverse structures such as nano-bar and cluster of elongated grains. Significant improvement in room temperature ferromagnetism (RTFM) was noticed by co-doping of Ce in Al-doped ZnO. Formation of bound magnetic polarons (Ce3+-Vo-Ce3+) was the primary mechanism responsible for the improvement in RTFM. [ABSTRACT FROM AUTHOR]

Laser-induced periodic surface structures (LIPSS) on biomedical stainless steel in air and water were systematically studied. The LIPSS exhibit in-plane curves near the ripple centres in the individual tracks of laser scan and the curving was opposite to the laser scan direction. The collective in-plane curving of LIPSS, a hitherto unknown feature for single train pulsed laser processing, is attributed to the accumulative effect of laser ablation and redeposition, which modifies the interference between the surface scattered wave and the incident laser beam. Combinations of media, scan-speed, and laser fluence, showed that the roughness can be increased by slowing the scan-speed. Ripples fabricated in the flowing water with slow scan-speed and high laser power are helpful for the hydrophilicity of biomaterials. A contact angle as low as 47.00 ± 9.35° is obtained towards high surface hydrophilicity. The results provide new insights on LIPSS about their formation and biomedical applications. [ABSTRACT FROM AUTHOR]

An introduction to this issue of "Materials Science and Technology" is presented.

The article presents an acknowledgement to authors who contributed in the publication of the September 2006 issue of the journal "Materials Science and Technology."

The present study is in sequel to the previous research (Phys. Chem. Chem. Phys. 16 (2014) p. 19122), where a solution-based nucleation and growth approach that involved direct epitaxial nucleation of nanofibres of poly(3-hexylthiophene) (P3HT) on carbon nanotubes (CNTs) for potential use as next-generation building blocks for applications including field-effect transistors and photovoltaic devices, was described. Also presented was a theoretical analysis of epitaxial mechanism of nucleation and growth of semiconducting conjugated polymers notably, P3HT on CNTs. In the present study, we elucidate the impact of molecular weight of P3HT on structural morphology and photophysical properties. The change in average molecular weight of P3HT from ~14 to ~60 kDa resulted in several structural changes, even though the mechanism of nucleation and growth continued to be epitaxial process. In the case of high-molecular weight P3HT, the crystallized fibrils were ~200–400 nm in length and ~2–3-nm thick. In contrast, for the low molecular weight, the fibrils were significantly longer (>5 μm) in length and ~800–1000-nm thick, which are envisaged to involve chain folding in relation to shorter fibrils. Furthermore, the graft density of fibrils crystallized on CNTs was remarkably higher for the high-molecular weight P3HT such that the connectivity between successive fibrils is anticipated to be through very small tie-molecules. On the other hand, the graft density of low-molecular weight P3HT crystallized on CNTs was low. Thus, the interconnectivity between successive fibrils is anticipated to involve large tie-molecules. The differences in connectivity between successive fibrils (besides the structural morphology), for low- and high-molecular weight P3HT, would at least, in part, impact the charge carrier mobility. [ABSTRACT FROM AUTHOR]

We describe here the combined efforts of engineering and biological sciences as a systemic approach to fundamentally elucidate osteoblast functions in functionally graded Ti-6Al-4 V mesh structures in relation to uniform/monolithic mesh arrays. First, the interconnecting porous architecture of functionally graded mesh arrays was conducive to cellular functions including attachment, proliferation, and mineralization. The underlying reason is that the graded fabricated structure with cells seeded from the large pore size side provided a channel for efficient transfer of nutrients to other end of the structure (small pore size), leading to the generation of mineralized extracellular matrix by differentiating pre-osteoblasts. Second, a comparative and parametric study indicated that gradient mesh structure had a pronounced effect on cell adhesion and mineralization, and strongly influenced the proliferation phase. High intensity and near-uniform distribution of proteins (actin and vinculin) on struts of the gradient mesh structure (cells seeded from large pore side) implied signal transduction during cell adhesion and was responsible for superior cellular activity, in comparison to the uniform mesh structure and non-porous titanium alloy. Cells adhered to the mesh struts by forming a sheet, bridging the pores through numerous cytoplasmic extensions, in the case of porous mesh structures. Intercellular interaction in porous structures provided a pathway for cells to communicate and mature to a differentiated phenotype. Furthermore, the capability of cells to migrate through the interconnecting porous architecture on mesh structures led to colonization of the entire structure. Cells were embedded layer-by-layer in the extracellular matrix as the matrix mineralized. The outcomes of the study are expected to address challenges associated with the treatment of segmental bone defects and bone-remodeling through favorable modulation of cellular response. Moreover, the study provides a foundation for a new branch of functionally graded materials with interconnected porous architecture. [ABSTRACT FROM AUTHOR]

Chitosan is a natural polymer, which has similar structure and bioactivity with glycosaminoglycan, and is a potential material for use as injectable hydrogels. Authors elucidate structure-property relationship with particular focus on chitosan-based injectable hydrogels, and their application as biomaterials. The different gelation approach, including physical cross-link, chemical cross-link, ionic cross-link and supramolecular interaction, enable a variety of chitosan-based injectable hydrogels to be formed. These gelation methods have significant impact on the structure and properties of hydrogels, which governs their use as tissue engineering scaffold and drug delivery vehicle. [ABSTRACT FROM AUTHOR]

The development of robust nano‐ and microstructured catalysts on highly conductive substrates is an effective approach to produce highly active binder‐free electrodes for energy conversion and storage applications. As a result, nanostructured electrodes with binder‐free designs have abundant advantages that provide superior electrocatalytic performance; these include more exposed active sites, large surface area, strong adhesion to substrates, facile charge transfer, high conductivity, high intrinsic catalytic activity, and fine‐tuning of its electronic nature through nanostructure modification. Notably, the interface chemistry of an electrocatalyst plays a significant role in their optimized electrocatalytic activity and stability. This review provides an overview of recent progress in nano‐ and microstructured catalysts, such as one, two, and 3D catalysts as binder‐free electrodes for electrocatalytic water splitting via the hydrogen evolution reaction and oxygen evolution reaction, and beyond. Furthermore, this review focuses on the current challenges and synthesis strategies of binder‐free electrodes, with a focus on the impact of nanostructure on their functional property relationships and enhanced bifunctional electrocatalytic performance. Finally, an outlook for their future advances in energy conversion and storage is provided. [ABSTRACT FROM AUTHOR]

The influence of aging pre-treatment on the hot deformation of a commercial alloy 800H was investigated through uniaxial compression tests. Aging pre-treatments were performed at 750°C for 0h, 5h, 10h, 20h and 50h, followed by compression tests at 750°C with strain rates of 0.01s-¹, 0.1s-1 and 1s-¹. The flow curves signified that the peak stress decreased evidently with increasing aging time. The microstructural analysis of alloy 800H after aging at 750°C for 50h indicated that the predominant precipitates are block-shaped Cr23C6 and cube-shaped Ti(C,N). The formation of grain-boundary Cr23C6 results in the segregation of Cr and C with the depletion of Ni at the grain boundaries. The kernel average misorientation maps after hot deformation demonstrates that the grain-boundary precipitates induce the pinning force to change the distribution of local misorientation and two different deformation patterns were defined to characterize the substructure developed near the grain boundaries. [ABSTRACT FROM AUTHOR]

A low carbon bainitic steel with varying strength was obtained through change in the thermo-mechanical processing parameters. In this regard, we elucidate the relationship between processing parameters, microstructure, and mechanical properties. The study underscores that the volume fraction of martensite-austenite (M-A) constituent is strongly governed by the rolling reduction ratio. The tensile strength was increased with increase in the volume fraction of lath bainite (LB) and M-A constituent, while the yield strength increased monotonically with increase in the volume fraction of LB, and was not sensitive to the volume fraction of M-A constituent. Acicular ferrite (AF) was responsible for high impact energy. Large blocky M-A constituent facilitated initiation of cracks at the M-A constituent/matrix interface, while small M-A constituent of size less than 1μm was helpful in improving toughness. The volume fraction of retained increased austenite with increase in rolling reduction ratio, which neutralized the negative effect of the increase in the volume fraction of M-A constituent on impact toughness, contributing to improvement in toughness. [ABSTRACT FROM AUTHOR]